As a toy in which a plurality of movable machines such as tanks are remote-controlled in the same place and firing is conducted among the movable machines, for example, a system disclosed in Japanese Patent Application No. 2713603 is known. In this system, each transmitter includes a device that transmits data for remote-controlling a corresponding movable machine by means of a radio wave. Each movable machine includes a device for emitting infrared rays toward another movable machine, a device for receiving data from the transmitter, and a device for sensing infrared rays of another movable machine. Each movable machine controls its own operation in accordance with data supplied from the transmitter, and emits infrared rays to other movable machines. If the movable machine senses infrared rays emitted by another movable machine, the movable machine judges itself fired upon.
In addition, in the above-mentioned system, a device for managing infrared ray emission time of each movable machine is provided separately from the transmitter and the movable machine. Each movable machine can determine which movable machine has fired upon itself.
In the above-mentioned invention, it is suggested that firing power may be set for each movable machine because it is possible to determine which movable machine has fired. However, its concrete configuration is not shown. Furthermore, there is a problem that a device for managing the infrared ray emission time required for determining the movable machine that has fired must be provided separately from the transmitter and the movable machine, in order to set the firing power for each movable machine. As the system becomes complicated, therefore, the production cost increases.